The present disclosure relates generally to semiconductor manufacturing. Specifically, the present disclosure relates to devices with line-end to line-end spaces and a dielectric film within those spaces.
The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component that can be created using a fabrication process) has decreased.
Some semiconductor devices include a multitude of gates laid out in parallel lines on the substrate. The gates are much longer than they are wide, and there are typically multiple gates in a single line arranged end-to-end. The space between parallel lines is referred to herein as “line-to-line spacing,” and the spacing between gates in the same line is referred to herein as “end-to-end spacing.” The gates are formed with sidewall spacers surrounding dummy gates. The film used to make the sidewall spacers does not completely fill either the line-to-line gaps or the end-to-end gaps. A Contact Etch Stop Layer (CESL) is then formed over the gates, and an interlayer dielectric (ILD) is formed over the CESL. The ILD is used to fill the gaps between the parallel lines and also to fill the end-to-end gaps.
Portions of the ILD, CSEL, and sidewall spacer film are then removed, exposing the dummy gates. However, these processes can leave an air gap in some end-to-end spaces as the ILD is removed. Subsequent deposition of gate metal can leave metal in the end-to-end gaps, interfering with subsequent overlay box alignment and causing shorts at contacts. Therefore, what is needed is an improved semiconductor device and method for making the same.